In the run-up to Twitter's IPO, Twitter and Facebook are locked in an increasingly fierce battle over the commercial future of Social TV - how television viewers discuss and engage with TV programming and advertising via social networks.

This spontaneous viewer behaviour, enabled by the boom in social media, smartphones and tablets, is impacting the global television-advertising ecosystem: ratings, tune-in, commercials, sponsorship, programming, formats and distribution.

The rival social networks are continuously launching multiple Social TV initiatives:

Creating innovative Social TV features for their users

Developing new business opportunities

Striking key international partnerships with multiple broadcasters, advertisers and distributors

Twitter's Amplify product, for instance, shows its users instant replays of exciting sports highlights embedded in a tweet, and gains Twitter and the broadcaster revenue from sponsor pre-roll ads.

Broadcaster partners include CBS, NBCUniversal, Viacom (US and international), ESPN and TF1, with sponsors such as AT&T, Coke Zero, Ford, General Electric and Unilever.

Facebook's Public Feed and Keyword Insights data tools enable broadcasters to engage Facebook users by displaying their real-time reactions and opinions within TV shows, which also gives the social network valuable on-air promotion.

Partners include ABC, BSkyB, CNN, Fox Sports and NBC, for Dancing with the Stars, sports and news programming.